In the manufacture of semiconductor devices, fine processing by lithography using a photoresist composition has conventionally been performed. The fine processing is a processing method of forming a thin film of a photoresist composition on a substrate to be processed such as a silicon wafer; irradiating the thin film with an active ray such as ultraviolet ray through a mask pattern having a semiconductor device pattern depicted therein, thereby carrying out development, and etching the substrate to be processed such as a silicon wafer with the obtained photoresist pattern as a protection film. However, with the higher integration of semiconductor devices in recent years, an active ray to be employed tends to have a shorter wavelength, namely, shift from KrF excimer laser (248 nm) to ArF excimer laser (193 nm). Accordingly, the influence of diffuse reflection of the active ray on the substrate or the influence of standing waves has become a serious problem. Consequently, a method of providing an anti-reflective coating (bottom anti-reflective coating, BARC) between a photoresist and a substrate to be processed has been widely studied. For example, a photosensitive resist underlayer film-forming composition containing a polymer having an acrylamide structure is disclosed (refer to Patent Document 1).
A resist underlayer film-forming composition containing a polymer having a unit structure of hydroxyacrylamide is disclosed (refer to Patent Document 2).
An anti-reflective coating-forming composition containing a polymer having a unit structure of hydroxyalkylenemethacrylamide and a unit structure of aromatic alkylene methacrylate is disclosed (refer to Patent Document 3).
In the future, when a finer resist pattern is further pursued, a problem about resolution or a problem of collapse of a resist pattern after development should arise, whereby reduction of the film thickness of a resist is desired. It is therefore difficult to attain a resist pattern film thickness sufficient for processing a substrate, and there has arisen a need for a process for allowing not only a resist pattern but also a resist underlayer film formed between a resist and a semiconductor substrate to be processed to function as a mask in substrate processing. As the resist underlayer film for such a process, unlike conventional high etch rate (high etching rate) resist underlayer films, there is a growing demand for a resist underlayer film for lithography having a selection ratio of dry etching rate close to that of a resist, a resist underlayer film for lithography having a selection ratio of dry etching rate smaller than that of a resist, and a resist underlayer film for lithography having a selection ratio of dry etching rate smaller than that of a semiconductor substrate.
An organic hard mask layer-forming composition having an acrylamide structure and being removable by an alkaline aqueous solution is disclosed (refer to Patent Document 4).